Mechanical sanders



Dec. 4, 1956 MASATSUGU MlNAMl 2,77

MECHANICAL SANDERS Filed March 13, 1954 INVENTOR MA SA T5060 M/lVA/W BYM /Gin;

ATTORNEYS United States Patent MECHANICAL SANDERS Masatsugu Minami,Meguro-ku, Tokyo, Japan Application March 18, 1954, Serial No. 417,162

3 Claims. (Cl. 51-141) The present invention relates to mechanicalsanders and is more particularly directed to a machine for sanding thesurface of sheet material.

The principal object of the present invention is to provide a sanderwhich will produce a finely polished surface upon the material beingtreated and which presents a fresh surface of a sanding belt to thematerial without permitting the accumulation of sand dust at the pointof sanding.

A further and equally important object of the invention is to provide amechanically driven sander which will smoothly and evenly sand widesurfaces of sheet material in a continuous manner.

A further object of the invention is to provide a sander which attacksthe material being treated from a plurality of directions at the sametime and also which supports the material while being sanded.

Further objects of the invention will be in part pointed out and in partobvious from the following description of the accompanying drawings inwhich;

Fig. 1 is a side elevation of the present device.

Fig. 2 is a top plan view of Fig. 1; and

Fig. 3 is a detail view taken on line a-a of Fig. 1 showing the relativeposition of the sanding belts, pressing belts and feed rollers only.

Referring now more particularly to the accompanying drawing, whereinlike and corresponding parts are designated by similar referencecharacters, numeral 1 indicates an endless belt having a sanding surfaceupon the exterior thereof and may be made of rubber or cloth with anemery cloth or sand paper outer surface. Said belt extends around a pairof spaced apart rotatably supported pulleys 2 positioned for driving andguiding said belt in a substantially straight line. A pulley 3 isfixedly connected to one of said pulleys 2 and is driven by a belt Bextending around pulley of a driving motor M.

A further pulley 4 is fixedly connected to pulley 3, but is of a smallerdiameter. A rotatably supported pulley 5 is connected by means of a beltto pulley 3 and is of a larger diameter than said pulley 4.

A pair of pulleys 6 are rotatably supported and spaced apart and have anendless pressing belt 7 extending therearound in line with and parallelto belt 1. One of said pulleys 6 is fixedly connected to pulley 5 forbeing driven thereby.

A frame 8 rotatably supports all of said aforementioned pulleys.

A tensioning roller 9 is pivotably connected to frame 8 and bearsupwardly against belt 1 due to the counter balancing Weight 10.

Similarly a roller 11 bears upwardly against belt 7 and is spring loadedthrough the medium of spring 12 tending to pivot said roller upwardly.Beams 13 extend between the standards of frame 8 and pivotably supportroller 11 while rotatably supporting pulleys 5 and 6.

A substantially straight and fiat guide 14 is adjustably supported by abeam 13- and is spaced at short distance ice above but parallel tobelt 1. Belt 7 slides along the bottom surface of said guide 14 forbeing guided thereby.

Belt 7 which may be made of steel, rubber or cloth has a series ofspaced apart pliable shoes 15 mounted on its outer surface. Said shoes15 are made of a pliable and resilient material such as soft rubber,sponge rubber or bristles in the manner of a brush.

A further endless belt 1 extends side by side with belt 1 and parallelthereto. This belt 1' has a sanding outer surface and similar drivingand supporting elements which are substantially identical with theircounterparts for said belt 1. That is, pulleys 2' rotatably mounted uponframe 8 have belt 1' extending therearound and are driven by a smallerpulley 3' fixedly connected to one of said pulleys 2' and rotated by abelt B driven by a motor M.

An endless pressing belt 7 is movably supported by pulleys 6 rotatablysupported by said frame with said belt 7' extending between and in linewith belt 1. One of said pulleys 6' is fixedly connected to a pulley 5'which is driven by an endless belt connected to a pulley 4 of a smallerdiameter which in turn is fixedly connected to pulley 3 for rotationtherewith.

Pressing belt 7 has a spaced apart series of shoes 15 similar to shoes15 mounted on the exterior surface there of and positioned for pressingagainst belt 15 therebeneath. A straight and elongated guide plate 14 isadjustably mounted on beam 13' and positioned for guiding belt 7 in astraight line above belt 1.

A plurality of rollers 16 are rotatably supported by suitable means, notshown, parallel to, but spaced below guides 14 and 14'. The axis ofthese rollers extends substantially parallel with the longitudinaldirection of belt 1, 1', and 7, 7.

In the operation of the present machine, a piece of sheet material 17,for example a plywood panel, is pushed between rollers 16, 16' in adirection substantially perpendicular to belts 1, 1. Said belts 1, 1'are driven in opposite directions to one another by their respectivemotors M, M, while belts 7, 7 are driven in the same direction as thesanding belt beneath, but at a slower speed due to the differences indiameter of the pulleys 4 and 5 and 4' and 5'.

Guide 14, 14' guide the belts 7, 7' respectively in a straight line sothat the shoes 15, 15 press against belts 1, 1' which are moving at agreater speed than said shoes. Accordingly, belts 1, 1 are caused tomove in a straight line across the material 17 but. in oppositedirections to one another for evenly and smoothly polishing the surfaceof said material.

With the progressing feeding of sheet 17, the sanding belt 1 andpressing belt 7 are driven by motor M with the pressing belt locatedinside of the sanding belt and running at a speed of about 500 feet perminute for example, pressing the sanding belt through the sanding shoes15. The sanding belt 1 which is pressed by said shoes 15 against theboard 17 runs faster than said pressing belt 7 as a rotative speed ofabout 4000 feet per minute for example, with the result that the belt 1sands the surface of material 17 with a fresh portion of its sandingsurface carrying the resulting sand dust from the sheet material whilethe sanding surface which has previously contacted said material runsahead of the sanding position. It is an outstanding feature of thepresent invention that the lower speed of the pressing belt relative tothe speed of the sanding belt causes said sanding belt to contact thesheet material with a fresh portion of its sanding surface therebyeliminating the accumulation of sand dust at the sanding position.

The present device is capable of considerable modification and suchchanges thereto as come within the scope of the appended claims aredeemed to be a part of the present invention.

nzaterial during sanding for movement in one direction and in asubstantially straight 'flat position, \an endless driven belt having anexterior sanding surface, 'means movably supporting-and directing saidbelticrosswise of a face-ofthe sheet material being sanded and madirection substantially perpendicular to the direction of movement ofsaid material, an endless pressing belt, means 'movably supporting anddirecting said pressing belt for movement in line With, spaced above,parallel to said sanding belt, means for driving said pressing belt at aspeed differing from that of said sanding belt, and a plurality ofspaced apart pliable shoes carried by said pressing belt and positionedfor rubbing against said sanding belt and pressing the portions of saidsanding belt therebeneath against said sheetmaterial.

2. A machine for sanding sheet material comprising means for movablysupporting and guiding the sheet material in a given direction andmaintaining said material in substantially a straight flat position, aplurality of endless belts each having an exterior sanding surface,means movably supporting and directing said belts laterally of saidsheet material With said sanding surface of each belt being in contactwith said sheet material on a line substantially perpendicular to thedirection of movement of said material, means for driving said belts inopposite directions, a plurality of endless pressing belts, meansmovably supporting and directing said pressing belts each in line with,spaced above and parallel to one of said sanding belts, means fordriving each of said pressing belts at a speed difiering from that of,but in the same direction to its respective sanding belt and a pluralityof series of pliable shoes with each series thereof carried by one ofsaid pressing belts and guided thereby against the portion of itsrespective sanding belt therebeneath pressing said sanding belt againstsaid sheet material.

3. A machine for sanding sheet material as claimed in claim 1 wherein anelongated straight guide is adjustably positioned in line with theportion of said pressing belt above said sheet material for beingcontacted by and guiding said belt whereby said shoes are caused topress against those portions only of said sanding belt passingthercbeneath and thus said portions of said sanding belt are pressedagainst said sheet material.

References Cited in the file-of this patent UNITED STATES PATENTS685,328 Gale Oct. 29, 1901 808,180 Tyden Dec. 26, 1905 891,251 HarbersJune 23, 1908 1,043,194 Blevney Nov. 5, 1912

